
\(\bullet \)  HACS [1]} includes \(504K\)  untrimmed videos retrieved from YouTube where each one is strictly shorter than 4 minutes. HACS clips consists of \(1.5M\)  annotated clips of 2-second duration and HACS Segments contains \(139K\)  action segments densely annotated in \(50K\)  untrimmed videos spanning 200 action categories.
